Facilities of this type usually work such that an alternating electromagnetic field is established in a section of the conveyed flow to be monitored by means of an alternating current generator and a transmitter coil system, whereby a variation of the signal of said field that is triggered by passage of a part is detected by a receiver coil system and serves, in conjunction with a downstream analytical circuit, for derivation of a detection signal which then triggers an information and/or elimination of said part. Facilities of this general type are described in terms of their application and structure, for example, in German Patent Application Nos. 37 14 009 A1 and 40 17 1 780 A1 and the references described therein. In this context, the detection signal serves for actuation of protective facilities, such as an optical and/or acoustic signaling device, of shut-off facilities of the conveying facility or for deviation of a conveyed flow containing an interfering part into a collection vessel or the like. In this context, the individual system components, such as a sensor unit, an analytical circuit, a sequence control system, etc., are usually combined into a module and electrically connected to each other by means of a wiring system. In case of a disturbance being present, this renders not only the troubleshooting more difficult, but also impedes flexibility in case the overall facility is to be adapted to changed working conditions.